Refractive index sensor based on an abrupt taper Michelson interferometer in a single-mode fiber

Abstract

A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode fiber that is terminated by approximately 500 nm thick gold coating. The sensitivity of the new sensor is similar to that of a long-period-grating-type sensor, and its ease of fabrication offers a low-cost alternative to current sensing applications.

Optofluidic refractometer using resonant optical tunneling effect

“…As one of the most popular commercial refractometers, Abbé refractometer could reach 10 −4 RIU by using the total internal reflection phenomenon. The wave optics based methods exploit the wave nature of light and mainly measure the RI by diffraction, 6 forward/backward scattering 7,8 and interference ͑e.g., Fabry-Pérot, [9][10][11] Mach-Zehnder, 12,13 double slits, 14 Michelson, 15 low coherence, 16 and fiber Bragg gratings 17,18 ͒. These methods improve the sensitivity to 10 −4 -10 −6 RIU since the wavelength acts naturally as the absolute reference of length.…”

High sensitivity refractive index sensor based on a tapered small core single-mode fiber structure

“…The maximum sensitivities for S-18.8, S-15.0, and S-12.5 are 4722.9 nm∕RIU (RI 1.4249-1.4319), 8353.6 nm∕RIU (RI 1.4256-1.4312), and 19212.5 nm∕RIU (RI 1.4304-1.4320), respectively. Taking into account that the OSA has a wavelength resolution of 0.01 nm, the RI sensor based on S-12.5 has an RI resolution of 5.025 × 10 −7 which, to the best of our knowledge, is significantly higher than previously reported [16][17][18][19][20]. It is noted that, in this Letter, the central wavelength of the spectral dip is determined as the 3 dB mean wavelength, which is a more reliable parameter compared to the central peak wavelength.…”

Experimental Study on the Application of the Michelson Interferometer

“…S is a laser light source, the plate G1 and G2 are glass plates of equal thickness, and G1 was coated with a layer of semi-permeable membrane. The beam is reflected and refracted on the semi-permeable membrane, and is divided into two perpendicular beams of light which are refracted light (1) and reflected light (2). The light (1) goes through plate G2, comes into the mirror M1 and then reflected back to G2, and finally get to screen p; the light (2)incidents to mirror M2, reflected and then goes through G1, finally get to screen p. These two beams meet the coherence conditions, and the interference fringes are displayed on the screen p. If the plane mirror M1 and M2 are perpendicular to each other, meet the inclinable interference conditions (which can be added to an expanding beam mirror to provide light incident at different angles); and If there is a small angle between the M1 and the M2, it belongs to the wedge interference device.…”

“…Michelson interferometer [1,2] is a common precision optical instrument in university laboratory, which uses the method of dividing amplitude to produce two coherent light beams. Measurements can be made by observing the changes in the fringe of the interference patterns.…”